1. Field of the Invention
Various embodiments are directed to methods and systems for determining whether an apnea event is caused by central or obstructive difficulties.
2. Description of the Related Art
Sleep apnea is defined in the field of respiratory therapy as a cessation of breathing during sleep lasting ten seconds or more. Sleep apnea may be characterized as either “central apnea” or “obstructive apnea.” Obstructive apnea is so named because the cessation of breathing is caused by an obstruction in the respiratory tract. For example, portions of the soft palate may collapse blocking the airway. In the case of obstructive apnea, the patient may attempt to inhale (i.e. has breathing effort), but the blockage prevents such an inhalation. Central apnea occurs when a sleeping person's central nervous system fails to instruct the diaphragm to retract to draw air into the lungs.
When a person is diagnosed with sleep apnea, a physician may need to determine whether the apnea is central or obstructive. In the related art, this determination may require the patient to make an overnight stay in a sleep diagnostic lab where numerous sensors and electrodes are placed on the patient. One of the key sensors used to determine whether breathing effort is present is a chest band. If breathing effort accompanies an apnea event then the patient has obstructive apnea. On the other hand, if no breathing effort corresponds with an apnea event, then it is most likely that the patient has central apnea.
While diagnosing central versus obstructive apnea in this fashion may be viable, it is a cumbersome process requiring the person to sleep in an unfamiliar environment coupled to a plurality of sensors and electrodes that are in most cases uncomfortable for the patient. Moreover, utilizing a sleep lab to diagnose central versus obstructive apnea can be very expensive, costing anywhere between $2,000 and $3,000 for an overnight study as of the time of this writing.
Thus, what is needed in the art is a method and related system to diagnose central versus obstructive apnea without the difficulties and expense associated with a sleep diagnostic lab environment.